Within the field of computing, many scenarios involve a social network, such as a database of users and associations established thereamong to represent various types of relationships (e.g., familial relations, friendships, and academic, professional, and business relationships). A user within a social network may establish a set of contacts, such as individuals with whom the user has a relationship, and may add new individuals as new relationships are formed. The social network may enable users to share with his or her contacts within the social network various types of messages, such as personal status messages. The social network may also allow a user to view the messages shared with the user by his or her contacts, such as a news feed comprising the personal status messages of the user's contacts.
Within a social network, a user may share with his or her contacts one or more content items hosted by various content sources. Such content items and content sources may include, e.g., web pages hosted by a website, images hosted by an image database, audio or video recordings hosted by an audio or video sharing service, and files hosted by a file server. A user may share these content items with his or her contacts in many ways, e.g., by adding an item to a set of shared content items that are of interest to the user and that may be viewable by all contacts of the user, or by sending a message to a contact that references a content item. The user may also annotate the content item with a comment, such as a summary of the content item or the user's personal opinions of the content item, and his or her contacts may also be permitted to annotate the content item with comments. The social network may promote this sharing of content items by generating a presentation thereof; e.g., upon request of a user, the social network may generate a content item feed comprising the content items that have been shared with the user by his or her contacts. For a particular content item hosted by a content source (e.g., an image hosted by an image database), the social network may be configured to integrate the content item with the presentation, or to provide a reference to the content item hosted by the content source (e.g., a preview version of an image hosted by the image database, and a hyperlink to an area of the image database where a full version of the image may be viewed). The content source may also permit users to submit comments regarding a content item.